Process for cleaning rugs



in such a fabric with constant use.

Patented May 25, 1943 PROCESS FOR CLEANING RUGS Varton MardirasKalusdian, New York, N. Y., as-

signor to The Mathieson Alkali Works, Inc., New York, N. Y., acorporation of Virginia No Drawing. Application June 2, 1938, Serial No.211,391

9 Claims.

This invention relates to an improved process for cleaning fabric floorcoverings, and in particular wool-pile and wool texture rugs andcarpets.

In the past, fabric floor coverings during cleaning have customarilybeen subjected to shampoolng treatments with soap solutions preceded byvacuum and beating treatments and followed by cumbersome rinsing anddrying steps. One of the greatest disadvantages experienced with suchprocesses has been the difliculty of causing proper loosening andeventual complete removal of the adhesive dirt held at the base of thepile by soot and other greasy materials which collect A further majordifficulty has been involved in the complete elimination of the soapsolution from the rug and particularly from the base of the pile aftershampooing. In spite of copious rinsing, satisfactory removal of soapfrom a pile fabric is seldom accomplished. As a result of failure tocompletely remove the soap it remains as acoating on the fibers, thusincreasing the tendency of dust particles to adhere to the fiber in sucha way that ordinary cleaning methods including the use of vacuumcleaners fail to remove such adhering dirt. quently becomes rancid, thuspreventing the pile from regaining its fresh, springy appearance.

In the process of the present invention, which is characterized by itssimplicity as well as economy of operation, such difliculties are eithernot encountered or are largely overcome. In accordance with myinvention, the fabric floor covering to be cleaned is treated with anaqueous solution formed by dissolving in water a stable calciumhypochlorite, sodium carbonate in excess of that necessary to react withall of the calcium present, and a synthetic organic water solubledetergent salt which does not produce an insoluble precipitate in thepresence of calcium ions. An acid salt, for example, sodium bicarbonate,in predetermined quantity to produce a solution of In addition, the soapresidue fredesired pH may advantageously be added to this solution. Theuse of such cleansing solutions is particularly advantageous in thecleansing of wool-pile and wool texture rugs or carpets or the like. Bythe term rug" as used herein I intend to refer to fabric floor coveringsincluded within these just mentioned classifications.

My process consists essentially in the treatment of a rug with anaqueous solution having dissolved therein the above-listed constituents.In the cleaning of certaintypes of rugs, and'in particular pile ,rugs,increased efflciencies are obtained-by the use ,of a two-step treatmentwhich comprises treating the rug on its reverse side with a quantity ofthe referred to solution, and then treating the right side or pile sideof the rug with a further quantity of the same solution. Due to theincreased wetting and penetrating power of the solutions used in myprocess, when applied to the reverse side of the rug, the solutionpenetrates to the base of the pile and hydrolyzes the greasy, wax-likedeposits which are there deposited, thus freeing dirt particles andfacilitating the emulslflcation and removal of such particles duringthesubsequent cleaning step on the right-or top side of the rug.

The solution which I employ in the process of my invention may beprepared for use by dissolving predetermined proportions of the ,drysalt constituents in water, or it may with advantage be prepared bydissolving in water a proportion of a dry stable salt mixture whichcontains the above-mentioned solid materials. Dry stable salt mixtureswhich may be used for this purpose are described in my eopendingapplication Serial No. 197,867, filed March 24, 1938.

The calcium hypochlorite which I prefer to use in the cleaning processof my invention is one which is a stable product high in availablechlorine and low in calcium chloride. Characteristically thishypochlorite contains upwards of 50% available chlorine and withparticular advantage upwards of The free lime content is preferablymaintained at a low value. The calcium hypochlorite referred to hereinas useful in my process is not to be confused with the conventionalbleaching powder or chlorinated lime from which it differs materially,both as to chemical constitution and in its exceptionally high contentof available chlorine. As examples of calcium hypochlorite productssuitable for use in the process of the present invention may bementioned the products whose preparation is described in United StatesPatents Nos. 1,481,039,.

1,481,040, 1,713,650, 1,713,654 1,713,668 and 1,713,669. The termcalcium hypochlorite" as used herein refers to a product having theproperties just described.

The material above-referred-to as a synthetic organic water solubledetergent salt may be chosen from a wide variety of organic compoundshaving strong detergent and wetting action. The organic or non-polargroups of these detergent compounds include a wide variety of organicgroups. In addition to carbon, hydrogen and oxygen, these groups maycontain sulfur or nitrogen, or other elements commonly associated withthem in organic compounds. Such groups include saturated, orunsaturated, hydrocarbons,

ethers, thioethers, primary and secondary alcohols, thioalcohols,ketones, thioketones, and esters. These groups may furthermore containaromatic or heterocyclic ring structures. The polar groups contained inthe detergents used in my invention are more limited in number. They arin most cases di-, or. poly-basic acids of sulfur or phosphorus; thesulfur containing acid groups occurring usually as sulfate'or sulfonate.The cations which form the salts with the acid groups in these compoundsinclude the alkali metals. the alkaline earth metals and the ammoniumion as, for example, in a quaternary ammonium salt. The non-polar groupsmentioned above usually form anions in solution, but the non-polargroups in quaternary ammonium compounds form cations in solutions. Saltsof sulfated higher alcohols are generally useful as detergents in theherein described mixtures. An example of another class of satisfactorydetergent compounds are the salts of sulfonated long chain compounds.These are distinguished from the referred to sulfates by the fact thatthe sulfonic group is attached directly to a hydrocarbon group, whereasthe alcohol sulfates are in reality sulfuric acid esters of thealcohols. Specific examples of synthetic organic detergent salts usefulin the composition of my invention are sodium lauryl sulfate, sodiumlauryl sulfonate, sodium ethylene palmitate sulfonate, sodium ethylenemethyl lauramide sulfonate, and palmityl trimethyl ammonium chloride.Soaps react alkaline in water solution and form insoluble compounds withthe alkaline earth metals. Under the sam conditions the water solubledetergents of the present invention do notiorm. such insolublecompounds. They produce substantially neutral aqueous solutions,apparently owing to the'fact that their solubilizing groups are morestrongly acidic than the carboxyl group in soap with the result thattheir metallic salts are more nearly neutral. These detergent compoundstherefore do not contain the carboxyl group as such, but may contain itin a muzzled form,

. for example as an ester grouping. By the phrase synthetic organicdetergent sal as used in this application and in the claims, I refer toa detergent compound of the above-referred to type, and

r I intend to exclude organic compounds which may he classified as soapswhich ,give 'a strong alkaline reaction in aqueous solution and whichprecipitate insoluble compounds with the alkaline earth metals.

The cleaning solutions of this invention may contain as solutes thereferred to calcium hypochlorite, sodium carbonate, acid salt and asynthetic organic detergent in varying proportions. The amount of eachconstituent present is governed to some extent by the amount of cleaningwhich must be accomplished and by the properties of the material to becleaned. In the treatment of many fabrics the quantity of salt mixture.exclusive of the synthetic organic detergent, which is dissolved in agiven quantity of water may remain approximately constant, while theamount of this synthetic detergent is altered in accordance with thedetergent and solution penetration requirements of the particular fabriccleaned. In most cases, a quantity of total salt mixture between about 1lb. and 3 lbs. dissolved in 50 gallons of water will provide asatisfactory cleaning solution. For example. one pound of organicdetergent salt and one pound of a mixassess;

ture oi. calcium hypochlorite, sodium carbonate. and sodium bicarbonatedissolved in 50 gallons of water produces a solution particularlyadvantageous for the cleaning of the majority of pile rugs by thedescribed two-step method. In certain cases, however, other salt ratiosin which for example the synthetic organic detergent comprises about to/2 the weight of the remainder of the dissolved salts are preferred. Therelative proportions in which the various inorganic com-' ponents areadded to the solution: or are present in a previously prepared dry saltmixture are also determined with reference to the degree of detergencynecessary and with reference to the properties of the rug to be cleaned.When the salt mixture is dissolved in water the calcium of thehypochlorite is precipitated as insoluble calcium carbonate. The clearsolution may then be decanted and supplied to the cleaning operation.Sinc an amount of carbonate equivalent to the calcium ion present isremoved from the solution by this precipitation, the amount of soda ashpresent in the original mixture should be in excess of an amountequivalent to the calcium hypochlorite present. In this way an excess ofsodium carbonate will remain in the solution imparting thereto valuabledetergent properties. In many cases it is desirable to have the solutions used in alower pH range than that resulting in a solutioncontaining any substantial excess of soda ash. The pH value imparted tothe solution by excess sodium carbonate may advantageously be lowered toa desired value by adding to the solution a predetermined proportion ofan acid salt, such as, for example, sodium bicarbonate.

The dimculties hitherto experienced in the cleaning of rugs byshampooing with soap referred to above are overcome by the process of myinvention and many independent improvements attained. The loss ofsubstantial proportions of cleansing agent accompanied by theprecipitation of insoluble soaps when hard waters are used is avoidedsince the synthetic organic detergent salt used in my process does notproduce a precipitate in the presence of calcium ions. The increasedwetting and penetrating action of the solutions used in my processresult in increased eiliciency of soil removal and time of reaction ascompared to the results obtained by the use of soaps. All of the saltsused in my process are readily soluble thus facilitating the removal ofthe reagents from the rug and eliminating extensive rinsing operations.This property eliminates the disadvantages resulting from the soap whichadheres to the fiber of the rug in spite of extensive rinsing. In thecase of rugs having a sheen finish, the original sheen of the rug isrestored without adversely affecting the color of the rug. The colors ofthe rug are in fact freshened and the design, if there be one.clarified. Stains are removed and the rug is efficiently and completelydeodorized and disinfected.

The following will serve as illustrative examples of the use of myprocess in specific instances of rug cleaning.

Example I.A wool-pile rug from which loose dirt had been removed in anautomatic dust beating machine was laid face down on the floor and wetwith water. A cleansing solution was prepared by dissolving 1 lb. of asynthetic organic 'under such conditions.

proximately 72 F. The solution was thoroughlystirred and theprecipitated calcium carbonate allowed to settle. The clear solution wasfed by gravity into the center of a mechanical rotary brush with whichthe rugwas scrubbed in a lengthwise and crosswise direction. The 1118was then rinsed, turned over and scrubbed on the pile side with afurther quantity of the abovedescribed detergent solution. It ispreferable that the right side of the rug be squeegeed both before andafter treatment with the detergent solution. Following this treatmentthe rug is passed through a wringer and dried in a conventional manner.

Example II.An alternative procedure to the "floor method of Example 1'involves the use of an automatic feeder machine. The rug to be cleanedwas fed into a device having arranged therein rows of fiat brushes whichvibrate alternately across the entire width of the rug, each row ofbrushes being made up of several individual brushes. The rug is passedthrough the machine twice; in the first passage the brushes positionedabove the rug thoroughly scrub the reverse side of the rug which isuppermost, and in the second passage, after rinsing of the back of therug, the right side is scrubbed. The detergent solution is applied tothe rug just prior to its contact with the horizontally vibratingbrushes. The solution used in this example was the same solution as wasemployed in Example I.

While increased efllciencies are attained in the cleaning of rugs byfirst treating the reverse side and then the right side of the rug inaccordance with the process of my invention, it is frequently desirableto clean rugs under circumstances where the two-step process, includingthe necessary turning and rinsing, is impractical, such as. for example,when rugs are to be cleaned in the home. Treatment with a singlesolution in accordance with my process results in marked advantages overthe methods hitherto employed The following detailed cleaning treatmentfor a rug or carpet without removing it from the location where it isnormally used will serve to illustrate the application of the process ofmy invention under such circumstances.

Example II!.The rug in its normal position on the floor is treated witha strong vacuum.

It is then sprinkled with a cleansing solution,

such as was employed in the processes of Examples I and 11, until therug is well wet with solution but not saturated, and then scrubbed witha soft rotary brush. As much of the soiled detergent solution aspossible is removed bythe vacuum, the rug sprinkled with fresh water andthis, in turn, removed with the vacuum. In drying, the nap is brushed inone direction and the rug permitted to stand until completely dry.

In cleaning rugs which are particularly fragile it has been customary touse a dipping process in which the rug must be dipped a number of timesin various treating solutions. By my process, such a rug maybecompletely cleaned by a single dipping thus eliminating the use of largevolumes of liquid, and effecting considerable saving in the time ofworking.

I claim:

1. A process for cleaning rugs which comprises treating the rug with anaqueous solution formed by dissolving in water a stable calciumhypochlorite, sodium carbonate in excess of that necessary to react withall of the calcium prescut, and a synthetic organic water solubledetergent salt which does not produce an insoluble precipitate in thepresence of calcium ions, and

.rinsing the thus treated rug.

2. A process for cleaning rugs which comprises treating the rug with anaqueous solution formed by dissolving in water a stable calciumhypochlorite, sodium carbonate in excess of that necessary to react withall of the calcium present, sodium bicarbonate, and a synthetic organicwater soluble detergent salt which does not produce an insolubleprecipitate in the presence of calcium ions, and rinsing the thustreated rug. 3. A process for cleaning rugs which comprises treating therug with an aqueous solution formed .by dissolving in water a stablecalcium hypochlorite containing upwards of 50% available chlorine andwhich is substantially free of calcium chloride, sodium carbonate inexcess of that necessary to react with all the calcium present sodiumbicarbonate, and a synthetic organic water soluble detergent salt whichdoes not produce an insoluble precipitate in the presence of calciumions, and rinsing the thus treated rug.

4. A process for cleaning rugs which comprises treating the rug with anaqueous solution formed by dissolving in water a stable calciumhypochlorite containing upwards of 50% available chlorine and which issubstantially free of calcium chloride, sodium carbonate in excess ofthat necessary to react with all the calcium present, sodiumbicarbonate, and a water soluble detergent sulfate salt of a higheralcohol selected from the class consisting of the alkali metal alcoholsulfates, the alkaline earth metal alcohol sulfates and ammonium alcoholsulfates, and rinsing the thus treated rug.

5. A process for cleaning rugs which comprises successively treatingfirst the reverse side and then the right side of a rug with an aqueoussolution formed by dissolving in water a stable calcium hypochlorite,sodium carbonate in excess of that necessary to react with all of thecalcium present, sodium bicarbonate, and a synthetic organic watersoluble detergent salt which does not produce an insoluble precipitatein the presence of calcium ions, and rinsing the thus treated rug.

6. A process for cleaning rugs which comprises successively treatingfirst the reverse side and then the right side of a rug with an aqueoussolution formed by dissolving in water a stable calcium hypochloritecontaining upwards of 50% available chlorine and which is substantiallyfree of calcium chloride, sodium carbonate in excess of that necessaryto react with all of the calcium present, sodium bicarbonate, and awater soluble detergent sulfate salt of a higher alcohol selected fromthe class consisting of the alkali metal alcohol sulfates, the alkalineearth metal alcohol sulfates and ammonium alcohol sulfates, and. rinsingthe thus treated me.

' high molecular weight having detergent properties which does notproduce an insoluble precipitate in the presence of calcium ions, andrinsing asaomai' about 5 to the'weight of said other dissolved salts,and rinsing the thus treated rug.

9. A process for cleaning rugs which comprises treating the rug with'anequeous solution formed by dissolving in water a mixture comprising onepart of a synthetic organic water soluble detersent salt and one part ofa mixture consisting of about 25% by weight of a stable calciumhypochlorite, about 37% by weight of sodium carbonate, and about 37% byweight of sodium bicarbonate, and rinsing the thus treated rug.

VARTON MARDIRAS KALUSDIAN.

